The present invention relates generally to a catheter or cannula for infusion of oxygenated blood or other fluids into a patient for cardiopulmonary support and cerebral protection. More particularly, it relates to an arterial perfusion catheter with a deployable cerebral embolic protection assembly (CEPA) for protecting a patient from adverse effects due to emboli that are dislodged during cardiopulmonary bypass.
Over the past decades tremendous advances have been made in the area of heart surgery, including such life saving surgical procedures as coronary artery bypass grafting (CABG) and cardiac valve repair or replacement surgery. Typically, in order to gain access to the heart a median sternotomy is performed, which creates an open surgical field, conducive for the placement of cannulae and direct visualization for performing the required procedure. Heart activity generally ceases for some period of time, and cardiopulmonary support is provided by diverting blood through an extracorporeal circuit to maintain sufficient oxygenated blood flow to the body and brain while the heart is arrested. Cardiopulmonary bypass (CPB) is a technology that has made these advances possible.
Recently, however, there has been a growing awareness within the medical community as well as the patient population concerning the adverse affects associated with heart surgery, the large amount of trauma associated with median sternotomies, as well as well the physiological reactions associated with cardiopulmonary bypass. Chief among these concerns is the potential for stroke or neurologic deficit.
Clinical research has indicated that one of the primary causes of stroke or neurologic deficit is cerebral embolization. Emboli vary in size as well as physical properties and their sources vary. However, embolic materials include atherosclerotic plaques or calcific plaques residing within the ascending aorta or cardiac valves and thrombus or clots from within the chambers of the heart. Emboli may also be dislodged during surgical manipulation of the heart, the ascending aorta, cross-clamping, aortic cannulation or due to high velocity jetting (sometimes called the xe2x80x9csandblasting effectxe2x80x9d) from the aortic perfusion cannula. In addition, air can enter the heart chambers or the blood stream during surgery through open incisions or through the aortic perfusion cannula. As blood is pumped to the brain, either through the extracorporeal circuit or by the beating heart in an off-pump minimally invasive procedure, transient or mobile emboli can become lodged in the brain causing a stroke or other neurologic deficit. Clinical studies have shown a correlation between the number and size of emboli passing through the carotid arteries and the frequency and severity of neurologic damage. At least one study has found that frank strokes seem to be associated with macroemboli larger than approximately 100 micrometers in size, whereas more subtle neurologic deficits seem to be associated with multiple microemboli smaller than approximately 100 micrometers in size. In order to improve the outcome of cardiac surgery and to avoid adverse neurological effects it would be very beneficial to eliminate or reduce the potential of such cerebral embolic events.
Therefore, what has been needed and heretofore unavailable, is a catheter device for standard open chest surgery and for use in minimally invasive medical procedures that is simple and relatively inexpensive. One which is capable of isolating the circulation of the arch vessels, while still allowing the heart to perform the function of perfusing the body or alternatively one that can be used in conjunction with an extracorporeal circuit. The present invention solves these problems as well as others.
The terms downstream and upstream, when used herein in relation to the patient""s vasculature, refer to the direction of blood flow and the direction opposite that of blood flow, respectively. In the arterial system, downstream refers to the direction further from the heart, while upstream refers to the direction closer to the heart. The terms proximal and distal, when used herein in relation to instruments used in the procedure, refer to directions closer to and farther away from the operator performing the procedure. Since the present invention is not limited to peripheral or central approaches, the device should not be narrowly construed when using the terms proximal or distal since device features may be slightly altered relative to the anatomical features and the device position relative thereto.
In keeping with the foregoing discussion, the present invention takes the form of a catheter or cannula having a cerebral embolic protection assembly (CEPA) mounted on an elongated tubular catheter shaft. The elongated tubular catheter shaft is adapted for introduction into a patient""s ascending aorta either by a peripheral arterial approach or by a direct aortic puncture. The CEPA has an undeployed state where it is compressed or wrapped tightly around the catheter shaft and a deployed state where it expands to the size of the aortic lumen. The CEPA assembly can be passively or actively deployed. Various mechanisms are disclosed for both passive and active deployment.
Radiopaque markers and/or sonoreflective markers may be located on the catheter and/or CEPA. Preferably, a perfusion lumen extends through the elongated tubular catheter shaft to one or more perfusion ports upstream and/or downstream of the CEPA. Oxygenated blood is perfused through the perfusion lumen, through the beating heat or a combination of both. Any embolic materials that might be dislodged are captured or rerouted by the CEPA.
Embodiments are also described that combine the CEPA with an aortic occlusion device, which may be a toroidal balloon, an expandable balloon or a selectively deployable external catheter flow control valve. The combined device allows percutaneous transluminal administration of cardiopulmonary bypass and cardioplegic arrest with protection from undesirable embolic events, as well as differential perfusion.
In use, the CEPA is introduced into the patient""s aorta, either by a peripheral arterial approach or by direct aortic puncture, with the CEPA in a collapsed state. The CEPA is advanced across the aortic arch and into the arch and ascending aorta. When a portion of the CEPA is positioned in the ascending aorta between the aortic valve and the brachiocephalic artery, the CEPA is either actively or passively deployed. The position of the catheter and the deployment state of the CEPA may be monitored using fluoroscopy, ultrasound, transesophageal echography (TEE) or aortic transillumination using visible, infrared or near infrared light. Once the CEPA is deployed, oxygenated blood may be infused into the aorta through the perfusion lumen or alternatively the beating heart may supply all the blood or a combination of both. Any potential emboli are captured or rerouted by the CEPA and are thereby prevented from entering the neurovasculature. After use, the CEPA is returned to the collapsed position and the catheter is withdrawn from the patient.
Methods according to the present invention are described using the aortic catheter for occluding and compartmentalizing or partitioning the patient""s aortic lumen and for performing selective filtered aortic perfusion.